1. Field of the Invention
This invention relates to generally horizontal inclined rotary kilns of the type used to calcine various industrial products such as cement and petroleum coke. The term "rotary kiln" as used herein is intended to include generally horizontal inclined rotary devices having a feed end and a discharge end and in which the feed end is subjected to high temperatures, such as internally fired calcining kilns, rotary coolers for cooling hot particulate matter, roasting furnaces, reduction furnaces or the like.
More particularly, this invention relates to an improved means for cooling the feed end dam of a rotary kiln.
2. The Prior Art
Numerous techniques have been employed to protect rotary kiln internals from the effects of the high temperatures to which they are exposed. Essentially the entire inner surface of a typical rotary kiln is lined with refractory insulating material. In some cases this is the only protection provided. In other cases, special cooling means such as circulating liquids or jets of cooling gases have been employed to protect the discharge ends of rotary kilns.
U.S. Pat. No. 2,826,403 describes a cooling arrangement in which a cooling medium such as water is used to cool the discharge end of a rotary kiln.
U.S. Pat. No. 3,940,239 describes a cooling arrangement in which air is directed into an annulus about the discharge end of a rotary kiln.
U.S. Pat. Nos. 1,620,989 and 3,806,311 disclose use of liquid cooling at the discharge end of a rotating furnace.
Prior to this invention, the feed end dams of rotary kilns have been protected by refractory insulation.